Numerical serial data, such as the prices of stocks on any given date, is commonly presented graphically on a chart. For example, financial serial data is commonly presented in the form of time-series data, where the X axis stands for time and the Y axis stands for the financial data, such as stock price, volume of transactions, degree of change, or other values pertaining to stocks. Looking at such a chart, one may see the changes in the stock price as they occur over time and observe trends and patterns. Plotting more than one such series of numerical data on the same graph, one may also compare one stock to another stock or an index representing an aggregated behavior of a number of stocks.
Many factors determine a stock price, but the common graphical representation only depicts the price as a function of time. It does not characterize any of the factors that could have brought about the changes in the stock price.
For example, consider the stock price of a drug company on the day it announces successful clinical trials of a new drug it has been developing. This “event” in the life of the company whose stock is under consideration may explain a rise in the price of the company's stock on that particular date. Similarly, when two companies announce a merger, each of their stock prices are affected. Also, when a key executive resigns from a company, the company's stock price may be affected.
Techniques have been developed to associate events to stock prices. For example, U.S. Pat. No. 5,412,769 to Maruoka et al. discloses a method and system for retrieving time-series information. When a user enters a desired time point, news and event occurrences are retrieved from an event database and displayed on a designated area on a graph of the retrieved time-series information. However, the step of extracting events is not disclosed. The news and event information is classified by class. Trade price is the time-series information.
U.S. Pat. No. 6,041,331 to Weiner et al. discloses a category based information extraction and graphic visualization system and method. The invention extracts information from a plurality of documents for display according to a set of pre-defined categories. Subsequently, a visual representation of the extracted information is provided for users. However, the disclosure is limited, among other things, by its failure to teach or suggest text mining based extraction of events.
U.S. Pat. No. 5,414,838 to Kolton et al. discloses a computerized data retrieval system for extracting historical market information. A user forms a search query and a database search engine finds results. The results are formatted in both textual and graphic reports. The system can include domain knowledge in a query, including calendar events, national holiday, political elections, earnings report release, etc. However, the disclosure is limited, among other things, by its failure to teach or suggest extraction of events from sources outside the database.
The contents of aforementioned U.S. Pat. Nos. 5,412,769, 6,041,331, and 5,414,838 are incorporated by reference to the extent necessary to understand the present invention.